Ultraviolet (UV) curing has many applications in printing, coating and sterilization. UV-sensitive materials generally rely upon a particular amount of energy in the form of UV light to initiate and sustain the curing process (polymerization) within the materials. UV light fixtures, commonly known as UV lamps, provide the UV light to the materials for curing.
Using arrays of light emitting diodes (LEDs) in UV curing has several advantages over using arc lamps, including lower power consumption, lower cost, cooler operating temperatures, etc. Generally, the arrays consist of individual LED elements arranged in an X-Y grid or linear array on a substrate.
In curing applications, one challenge exists in having a high enough irradiance during the time period allowed to cause the polymerization or curing to occur. One means of increasing the irradiance in LED UV lamps involves reducing the divergence of the light. LEDS generally have light that exits at all angles. Reducing that divergence increases the light available at a target surface, increasing the irradiance.